Submitted to: Parasitology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/11/2000
Publication Date: N/A
Citation: Interpretive Summary: Sarcocystis falcatula is a single-celled parasite. It is transmitted to birds via feces of infected opossums. It causes mortality in several species of bird and can be confused with an other parasite, Sarcocystis neurona, that coexists in opossum feces. All reports of S. falcatula infections in birds are from North America. Scientists at the Beltsville Agricultural Research Center and the Virginia Tech and University in Brazi report another Sarcocystis falcatula-like organism from the South American opossum, Didelphis albiventris for the first time. This paper will be of interest to wildlife biologists, parasitologists and veterinarians.
Technical Abstract: An unidentified isolate of a Sarcocystis falcatula-like parasite was obtained from the lungs of budgerigars (Melopsittacus undulatus) fed sporocysts from a naturally-infected South American opossum, Didelphis albiventris from Brazil. Four captive budgerigars fed sporocysts from the opossum intestine died of acute sarcocystosis 8, 10, and 12 days after oral linoculation (DAI); 1 budgerigar was killed 12 DAI when it was lethargic. Schizonts and merozoites found in the lungs of the budgerigars reacted mildly with polyclonal S. falcatula antibody. The parasite was isolated in equine kidney cell cultures inoculated with lung tissue from a budgerigar that was killed 12 DAI. Two budgerigars inoculated subcutaneously with 100,000 culture-derived S. falcatula merozoites developed acute sarcocystosis and S. falcatula-like schizonts were found in their lungs 15 and 16 DAI. Four budgerigars kept as unfed controls in the same environment remained free of Sarcocystis infection. The parasite underwent schizogony in African green monkey kidney cells and bovine turbinate cells. Merozoites divided by endopolygeny, often leaving a residual body. Polymerase chain reaction studies using primers JNB33/JNB54 and Hinf I and Dra I digestion indicated that the isolate was not S. falcatula. Results of this study indicated that the South American opossum, D. albiventris, is a definitive host for yet another S. falcatula-like parasite.